string.contains() doesn't exist while working in chrome

Question

I have a code like:

var valid = viewName.contains('/');

which works fine in firefox browser. But in chrome it is undefined. Why is that so? Is it true that chrome has not such a method for string?

Is it OK to use indexOf instead of contains, is it supported in all browsers?

Answer 1

String.indexOf() is what I use and it will work fine.

  var strIndex = viewName.indexOf('/');
  if(strIndex == -1) {
     //string not found
  } else {
    //string found
  }

But, just in case you want to have a contains() function, you can add it to String as below:

 if(!('contains' in String.prototype)) {
       String.prototype.contains = function(str, startIndex) {
                return -1 !== String.prototype.indexOf.call(this, str, startIndex);
       };
 }

var valid = viewName.contains('/');
if(valid) {
  //string found
} else {
  //string not found
}

Answer 2

Support for this, in Firefox and Chrome too, is now disabled by default. If you land here looking for an up to date answer, you can view the reason why, and the new method name (which is String.includes) here.

Try:

yourString.includes('searchString')